1. Field of the Invention
The invention relates to a support apparatus provided with a member for displaceably supporting a movable member such as a rotating shaft, and a pump apparatus.
2. Description of the Related Art
Space equipment such as artificial satellites, space stations or the like, and other equipment used in outer space include many kinds of drive mechanisms in which a support apparatus, such as ball-and-roller bearing apparatuses, ball screw apparatuses, linear guide apparatuses and the like, for displaceably supporting a movable member is used. Fluoro grease is used as a lubricant in a support apparatus for use on earth, but evaporates in outer space is responsible for contamination of various equipment and decomposition due to radioactive rays, and so cannot be used there. In a support apparatus for equipment used in outer space, molybdenum dioxide, lead or silver is used, which is low in torque and stable.
As described above, equipment used in outer space, in particular, equipment used over a long term in artificial satellites, space stations or the like, are exceedingly difficult in the exchange of parts, and required high durability. A support apparatus for supporting a movable member provided in such equipment is desirably made simple in construction for the purpose of less failure, and constructed to dispense with the use of lubricant for preventing a degraded performance due to changes in the lubricant.
It is an object of the invention to provide a support apparatus which is simple in construction and dispenses with lubricant.
Also, it is an object of the invention to provide a pump apparatus which is simple in construction and provided with a bearing structure for supporting a rotating shaft, and which dispenses with lubricant.
The invention provides a support apparatus for displaceably supporting a movable member comprising slide members for slidably supporting the movable member, the slide members being formed of amorphous carbon.
According to the invention, a movable member can be supported by slide members formed of amorphous carbon. Amorphous carbon is high in abrasion resistance and possesses a low frictional property called a self-lubricating property, and slide members formed of amorphous carbon are used to smoothly slide relative to a movable member to, without using lubricant, enable supporting the movable member so that the movable member can be smoothly displaced. Accordingly, it is possible to obtain a support apparatus that is simple in construction and supports a movable member without the use of lubricant to enhance the durability of the support apparatus.
In the invention, it is preferable that the movable member comprises a rotating shaft and the slide members are slide bearing members for rotatably supporting the rotating shaft.
According to the invention, the slide bearing members formed of amorphous carbon can support the rotating shaft. It thereby is possible to reduce a gap between the rotating shaft and the slide bearing members and rotatably support the rotating shaft so as to cause stable rotation of the rotating shaft.
In the invention it is preferable that the slide members are arranged in a space in which a fluid is contained.
According to the invention, the slide members are formed of amorphous carbon and possess chemical resistance, so they are not subjected to chemical change by a fluid even when being provided in a space in which a fluid is contained. Besides, even if the fluid is one, either a strong acid or strong base, liable to chemically affect a mating member, the slide members are not subjected to chemical change by the fluid. The slide members can thereby preserve the function as slide members over a long term without being damaged by the fluid. Accordingly, the slide members can be suitably used in fluid flow passages.
In the invention, it is preferable that a gap between the movable member and the slide members is dimensioned to allow entry of the fluid due to the capillary phenomenon.
According to the invention, a fluid in the space enters between the movable member and the slide members. The slide members formed of amorphous carbon are not restricted in lubricant as in the case of slide members of metal, but can use a wide variety of fluids as lubricant. As described above, while lubricant is essentially unnecessary, the use of lubricant makes it possible to support the movable member in a further smoothly displaceable manner. Accordingly, a fluid in the gap can be used as lubricant so that a supporting state can be achieved to realize smooth displacement of the movable member.
In the invention, it is preferable that the fluid is liquid ammonia. According to the invention, the slide members possess chemical resistance, and are not subjected to chemical change even when a fluid is liquid ammonia, so that they can preserve their function as slide members over a long term. Moreover, it is possible to make use of liquid ammonia as a favorable lubricant. Accordingly, the slide bearing members can be favorably used in a space in which liquid ammonia is contained.
In the invention it is preferable that the support apparatus is mounted on equipment used in outer space.
According to the invention, the support apparatus can be enhanced in durability, so that it is suitably usable for equipment, such as artificial satellites, space stations or the like, which are used in outer space, and whose parts are difficult to exchange.
The invention provides a pump apparatus comprising a rotating shaft, slide bearing members formed of amorphous carbon for rotatably supporting the rotating shaft, drive means for drivingly rotating the rotating shaft and a pump body connected to the rotating shaft, for pumping a fluid.
According to the invention, the drive means is used to drive the rotating shaft to drive the pump body connected to the rotating shaft to discharge a fluid. The rotating shaft is rotatably supported by a bearing apparatus having slide bearing members. The slide bearing members are formed of amorphous carbon. Amorphous carbon is high in abrasion resistance and possesses a low frictional property called a self-lubricating property, and slide bearing members formed of amorphous carbon are used to smoothly slide relative to the rotating shaft to, without using lubricant, enable supporting the rotating shaft so that the rotating shaft can be smoothly rotated. Accordingly, it is possible to obtain a bearing apparatus which is simple in construction and supports the rotating shaft without the use of lubricant to enhance durability of the bearing apparatus, thus of the pump apparatus.
In the invention it is preferable that the pump apparatus further comprises a housing having a fluid flow passage which provides communication between a suction port and a discharge port, and that the rotating shaft is arranged in the housing, the slide bearing members are fitted in the fluid flow passage in the housing, the drive means comprises a rotor fitted in the fluid flow passage to be provided on the rotating shaft and a stator provided outside the housing to surround the rotor, and the pump body is provided midway of the fluid flow passage.
According to the invention, the drive means is used to drive the rotating shaft to drive the pump body connected to the rotating shaft so that a fluid sucked through a suction port is made to flow down the flow passage to be discharged through a discharge port. In this pump apparatus, the rotating shaft, the slide bearing members and the rotor are fitted into the flow passage. In this manner, the provision of the rotating shaft, the slide bearing members and the rotor in the flow passage eliminates the need of providing rotating constituents both inside and outside the flow passage through the housing, so that the whole pump apparatus can be made favorable in sealing quality relative to leakage of the fluid, the sealing construction can be made simple, and the pump apparatus can be made small in size.
With such construction, the slide bearing members are formed of amorphous carbon and possess chemical resistance, so they are not subjected to chemical change by a fluid even when being provided in a space in which a fluid is contained. Besides, even if the fluid is one, either strong acid or strong base, liable to chemically affect a mating member, the slide members are not subjected to chemical change by the fluid. The slide bearing members can thereby preserve the function as slide bearing members over a long term without damage by the fluid.
In the invention, it is preferable that a gap between the rotating shaft and the slide bearing members is dimensioned to allow entry of the fluid due to the capillary phenomenon.
According to the invention, a fluid in the flow passage enters between the rotating shaft and the slide bearing members. The slide bearing members formed of amorphous carbon are not restricted in lubricant as in the case of slide bearing members of metal, but can use a wide variety of fluids as lubricant. As described above, while lubricant is essentially unnecessary, the use of lubricant makes it possible to support the rotating shaft in a further smoothly displaceable manner. Accordingly, the fluid in the flow passage can be used as lubricant and so a pump apparatus can be achieved to provide for further smooth rotation of the rotating shaft.
In the invention it is preferable that the pump apparatus is a pump for circulating a refrigerant and the fluid is liquid ammonia as the refrigerant.
According to the invention, the slide bearing members possess chemical resistance, and are not subjected to chemical change even when the fluid is liquid ammonia, so that they can preserve the function as slide bearing members over a long term. Moreover, the slide bearing members can make use of liquid ammonia as a favorable lubricant. Without the use of freon gas, for the sake of global environmental protection, such liquid ammonia is used as a refrigerant favorably in the pump apparatus, in which the refrigerant is circulated.
Also, liquid ammonia as refrigerant can be used to cool the rotating shaft, the slide bearing members and the rotor and to maintain a stable performance of the pump.
In the invention it is preferable that the pump body is formed of amorphous carbon.
According to the invention, the pump body is formed of amorphous carbon, and so is not susceptible to chemical influences, whereby it is possible to realize a favorable pump apparatus that keeps the function of the pump body over a long term.
In the invention, it is preferable that the slide bearing members are radial bearings to bear the radial load of the rotating shaft, and the pump body is formed of amorphous carbon to bear the thrust load of the rotating shaft.
According to the invention, formation of the pump body of amorphous carbon can have the pump body fulfilling the function of thrust bearings and bearing the thrust load of the rotating shaft. Therefore, the load on the slide bearing members can be reduced. In this manner, load is imposed on the pump body to make it possible to reduce the slide bearing members in size and enhance durability of the pump apparatus.
In the invention, it is preferable that the pump apparatus is mounted on equipment used in outer space.
According to the invention, the pump apparatus can be enhanced in durability so that it is suitably usable for equipment, such as artificial satellites, space stations or the like, which are used in outer space, of which parts are difficult to exchange.